An integrated CAD tool for switching power supply design with electromagnetic interference prediction

A computer-aided tool for the design of switching power supplies integrating layout editor, autorouter, component library builder and EMI simulator is presented. The software takes on a modular approach and develops the PCB layout with EMI prediction. The prediction of EMI is achieved by SPICE simulation with suitable model assignments of EMI sources, components and PCB tracks. An off-line forward converter is built and measured to verify the simulated result. Finally, a performance index is introduced to act as an indicator for the EMC performance of a given PCB layout.